Patients with genital herpes were treated three times weekly for 12 weeks with 3 .times. 106 IU of alpha2b interferon (20 patients) or placebo (17 patients) administered by subcutaneous injection in a double-blind trial. Interferon had minimal effects on the suppression of recurrences and moderate toxicity (chills, fever, fatigue, and leukopenia), suggesting that this route and dosage of interferon may not be clinically useful for this indication.